This invention relates generally to golf putters, and more particularly to golf putters that incorporate mechanisms or indicia to improve alignment of the putter face relative to the target line and/or to improve striking the ball at the proper heel-to-toe position on the clubface. More particularly, the invention relates to golf putters having such alignment/positioning mechanisms or indicia that correct for the error produced by left or right eye predominance.
In the game of golf, consistent putting is one of the main requirements to produce a low score. One of the crucial factors in accurate putting is proper alignment of the clubface to the chosen target line at the point of ball contact during the stroke. The clubface should be perpendicular to the target line when the ball is struck. If the clubface alignment at the point of contact is open (the angle between the target line and the toe side of the clubface is greater than 90 degrees) or closed (the angle between the target line and the toe side of the clubface is less than 90 degrees), the ball will not travel along the intended target line.
Many putters incorporate a short visual alignment line on the top of the putter blade, the line being perpendicular to the clubface, in order to provide a visual reference for the proper clubface alignment. Research shows that about half of all golfers use the line on the top of the putter to align the clubface while the remainder use the leading edge of the putter. It is theorized that the reason many golfers ignore the alignment line and use the leading edge to align the putter perpendicularly to the target line is that the alignment line does not appear to them to be perpendicular to the clubface. This is a result of a condition known as eye predominance, where either the right eye or left eye is dominant when the golfer is comparing the alignment line to the leading edge of the putter clubface and the target line. The dominant eye causes the alignment line to appear to be skewed slightly open or closed relative to the clubface, and the golfer misaligns the putter accordingly.
A simple test for determining eye predominance is to have the golfer point at arm's length to an object in the distance. Without moving the pointer finger, each eye is individually closed. If the golfer has a dominant eye, the finger will remain pointing at the object with that eye open, but will not be pointing at the object with the other eye open. Statistically, about two-thirds of golfers are right eye dominant and about one-third are left eye dominant. A right-eye dominant golfer will tend to misalign the putter in the open position, since to this golfer the alignment line on the putter will falsely appear to be angled slightly above perpendicular, while a left eye dominant golfer will misalign the putter in the closed position, since to this golfer the alignment line on the putter will falsely appear to be angled slightly below perpendicular. The amount of misalignment tends to range from about 0.75 degrees to 2.0 degrees from perpendicular, with a misalignment angle of about 1.25 degrees being most prominent.
General examples of putter alignment devices or structures for providing a visual indicator to the golfer are shown in U.S. Pat. No. 3,033,574 to Partridge, U.S. Pat. No. 3,118,678 to Rohr, U.S. Pat. No. 3,199,873 to Surratt, U.S. Pat. No. 3,333,854 to White, U.S. Pat. No. 4,762,324 to Anderson, and U.S. Pat. No. 5,409,228 to Botsch. These patents show putters having both fixed alignment devices and adjustable alignment devices. The majority of these references show structures that are visually distracting. The least visually distracting structures are shown in the White and Anderson patents, where the alignment line or lines are inscribed or imprinted onto the top of the putter head and are contained within a half-circle outline, where the half-circle is positioned with its curved portion to the rear of the club. This visual design is similar to a well-known system for increasing the likelihood that the ball will be struck at the proper contact point in the heel-to-toe direction, shown for example in U.S. Pat. No. 3,408,074 to Antonious, U.S. Pat. No. 4,688,798 to Pelz, U.S. Pat. No. 4,809,977 to Doran et al., U.S. Pat. No. 4,872,683 to Doran et al., U.S. Pat. No. D471,245 to Tang et al., U.S. Pat. No. D471,940 to Tang et al., U.S. Pat. No. 6,471,600 to Tang et al., and U.S. Pat. No. 6,506,125, where golf ball sized circles or half-circles are mounted on the putter so as to be visible to the golfer from above. These designs operate on the theory that it is easier visually during the forward putting stroke to align one or more golf ball sized circles or half-circles with the actual ball being struck. None of these patents, however, are concerned with correcting misalignment due to right or left eye predominance, due to the fact that they do not incorporate alignment lines which can be visually misperceived and are attempting to provide visual alignment indicators of sufficient size and shape such that eye predominance will have a reduced detrimental effect on the proper alignment of the putter.
Several patents directly address the problem of eye predominance. For example, U.S. Pat. No. 3,680,860 to Elkins, Jr., discloses a mallet putter (a putter with a large, elongated head, as opposed to a blade putter) having a wide alignment stripe with a centered alignment line positioned on top of the club head, where the alignment line is angled so as to be non-perpendicular to the clubface. Obviously, the width and length of the stripe and line precludes use of the structure on blade putters. U.S. Pat. No. 5,839,970 to Lombardo shows an alternative approach to accounting for eye predominance that also requires a mallet putter. Multiple lines are provided, with the particular alignment line chosen on the basis of the distance of the putt. This system fails to take into account that the golfer should be aligning each point with a target line passing through a point at most a few feet in front of the ball, and therefore the multiple lines serve no useful purpose and will be detrimental to proper alignment. A better solution is provided in U.S. Pat. No. 5,429,366 to McCabe. This device provides a cylindrical module bearing an alignment line on one end, with the module mounted in the putter head such that the line can be rotated about the central axis of the module. Thus, to correct for eye predominance the module is rotated a slight amount and then fixed in place. A drawback to this design is that the line rotates about the axis of the module, such that the front end of the line will be shifted slightly left or right of the ideal heel-to-toe striking point and the back end of the line will be shifted slightly to the opposite side of the ideal heel-to-toe striking point. Thus, correction of the eye predominance affect results in a tendency for the golfer to strike the ball either too close to the toe or to close to the heel, since the golfer's eyesight is focused on the front of the alignment line. In addition, because the modular is circular when viewed from above, the golfer lacks additional reference indicia in order to ascertain that the clubface is perpendicular to the target line.
It is an object of this invention to provide a golf putter having alignment indicia that corrects the problem of misalignment caused by eye predominance, in a manner that is not visually distracting to the golfer and that does not detrimentally alter the balance, physical structure or performance characteristics of the putter. It is a further object to provide such a golf putter that does not suffer the drawbacks of previous attempts to address this problem.